防止常见XSS 过滤 SQL注入 JAVA过滤器filter

XSS : 跨站脚本攻击(Cross Site Scripting)，为不和层叠样式表(Cascading Style Sheets, CSS)的缩写混淆，故将跨站脚本攻击缩写为XSS。恶意攻击者往Web页面里插入恶意html代码，当用户浏览该页之时，嵌入其中Web里面的html代码会被执行，从而达到恶意攻击用户的特殊目的。

sql注入

所谓SQL注入，就是通过把SQL命令插入到Web表单提交或输入域名或页面请求的查询字符串，最终达到欺骗服务器执行恶意的SQL命令。具体来说，它是利用现有应用程序，将（恶意）的SQL命令注入到后台数据库引擎执行的能力，它可以通过在Web表单中输入（恶意）SQL语句得到一个存在安全漏洞的网站上的数据库，而不是按照设计者意图去执行SQL语句。

1、首先配置web.xml，添加如下配置信息：

    <!-- 解决xss & sql漏洞 -->  
    <filter>  
        <filter-name>xssAndSqlFilter</filter-name>  
        <filter-class>com.cup.cms.web.framework.filter.XssAndSqlFilter</filter-class>  
    </filter>  
    <!-- 解决xss & sql漏洞 -->  
    <filter-mapping>  
        <filter-name>xssAndSqlFilter</filter-name>  
        <url-pattern>*</url-pattern>  
    </filter-mapping>

2、编写过滤器

/** 
 *  
 */  
package com.cup.cms.web.framework.filter;  
import java.io.IOException;  
import javax.servlet.Filter;  
import javax.servlet.FilterChain;  
import javax.servlet.FilterConfig;  
import javax.servlet.ServletException;  
import javax.servlet.ServletRequest;  
import javax.servlet.ServletResponse;  
import javax.servlet.http.HttpServletRequest;  
/** 
 * @Author hithedy 
 * @Date 2016年2月2日 
 * @Time 下午2:01:53 
 */  
public class XssAndSqlFilter implements Filter {  
    @Override  
    public void destroy() {  
        // TODO Auto-generated method stub  
    }  
    @Override  
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {  
        XssAndSqlHttpServletRequestWrapper xssRequest = new XssAndSqlHttpServletRequestWrapper((HttpServletRequest) request);  
        chain.doFilter(xssRequest, response);  
    }  
    @Override  
    public void init(FilterConfig arg0) throws ServletException {  
        // TODO Auto-generated method stub  
    }  
}

3、包装器

    /** 
     *  
     */  
    package com.cup.cms.web.framework.filter;  
    import java.util.regex.Pattern;  
    import javax.servlet.http.HttpServletRequest;  
    import javax.servlet.http.HttpServletRequestWrapper;  
    /** 
     * @Author hithedy 
     * @Date 2016年2月2日 
     * @Time 下午2:03:19 
     */  
    public class XssAndSqlHttpServletRequestWrapper extends HttpServletRequestWrapper {  
        HttpServletRequest orgRequest = null;  
        public XssAndSqlHttpServletRequestWrapper(HttpServletRequest request) {  
            super(request);  
            orgRequest = request;  
        }  
        /** 
         * 覆盖getParameter方法，将参数名和参数值都做xss & sql过滤。<br/> 
         * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/> 
         * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖 
         */  
        @Override  
        public String getParameter(String name) {  
            String value = super.getParameter(xssEncode(name));  
            if (value != null) {  
                value = xssEncode(value);  
            }  
            return value;  
        }  
        /** 
         * 覆盖getHeader方法，将参数名和参数值都做xss & sql过滤。<br/> 
         * 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/> 
         * getHeaderNames 也可能需要覆盖 
         */  
        @Override  
        public String getHeader(String name) {  
            String value = super.getHeader(xssEncode(name));  
            if (value != null) {  
                value = xssEncode(value);  
            }  
            return value;  
        }  
        /** 
         * 将容易引起xss & sql漏洞的半角字符直接替换成全角字符 
         *  
         * @param s 
         * @return 
         */  
        private static String xssEncode(String s) {  
            if (s == null || s.isEmpty()) {  
                return s;  
            }else{  
                s = stripXSSAndSql(s);  
            }  
            StringBuilder sb = new StringBuilder(s.length() + 16);  
            for (int i = 0; i < s.length(); i++) {  
                char c = s.charAt(i);  
                switch (c) {  
                case '>':  
                    sb.append("＞");// 转义大于号  
                    break;  
                case '<':  
                    sb.append("＜");// 转义小于号  
                    break;  
                case '\'':  
                    sb.append("＇");// 转义单引号  
                    break;  
                case '\"':  
                    sb.append("＂");// 转义双引号  
                    break;  
                case '&':  
                    sb.append("＆");// 转义&  
                    break;  
                case '#':  
                    sb.append("＃");// 转义#  
                    break;  
                default:  
                    sb.append(c);  
                    break;  
                }  
            }  
            return sb.toString();  
        }  
        /** 
         * 获取最原始的request 
         *  
         * @return 
         */  
        public HttpServletRequest getOrgRequest() {  
            return orgRequest;  
        }  
        /** 
         * 获取最原始的request的静态方法 
         *  
         * @return 
         */  
        public static HttpServletRequest getOrgRequest(HttpServletRequest req) {  
            if (req instanceof XssAndSqlHttpServletRequestWrapper) {  
                return ((XssAndSqlHttpServletRequestWrapper) req).getOrgRequest();  
            }  
            return req;  
        }  
        /** 
         *  
         * 防止xss跨脚本攻击（替换，根据实际情况调整） 
         */  
        public static String stripXSSAndSql(String value) {  
            if (value != null) {  
                // NOTE: It's highly recommended to use the ESAPI library and  
                // uncomment the following line to  
                // avoid encoded attacks.  
                // value = ESAPI.encoder().canonicalize(value);  
                // Avoid null characters  
    /**         value = value.replaceAll("", "");***/  
                // Avoid anything between script tags  
                Pattern scriptPattern = Pattern.compile("<[\r\n| | ]*script[\r\n| | ]*>(.*?)</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Avoid anything in a src="http://www.yihaomen.com/article/java/..." type of e-xpression  
                scriptPattern = Pattern.compile("src[\r\n| | ]*=[\r\n| | ]*[\\\"|\\\'](.*?)[\\\"|\\\']", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Remove any lonesome </script> tag  
                scriptPattern = Pattern.compile("</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Remove any lonesome <script ...> tag  
                scriptPattern = Pattern.compile("<[\r\n| | ]*script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Avoid eval(...) expressions  
                scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Avoid e-xpression(...) expressions  
                scriptPattern = Pattern.compile("e-xpression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Avoid javascript:... expressions  
                scriptPattern = Pattern.compile("javascript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Avoid vbscript:... expressions  
                scriptPattern = Pattern.compile("vbscript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);  
                value = scriptPattern.matcher(value).replaceAll("");  
                // Avoid onload= expressions  
                scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
                value = scriptPattern.matcher(value).replaceAll("");  
            }  
            return value;  
        }  
    }